State of the art Precise Point Positioning (PPP) is currently based on dual-frequency processing of GPS and Glonass navigation systems. The International GNSS Service (IGS) is routinely providing the most accurate orbit and clock products for these constellations, allowing point positioning at centimeter-level accuracy. At the same time, the GNSS landscape is evolving rapidly, with the deployment of new constellations, such as Galileo and BeiDou. The BeiDou constellation currently consists of 14 operational satellites, and the 4 Galileo In-Orbit Validation (IOV) satellites are transmitting initial Galileo signals. This paper focuses on the integration of Galileo and BeiDou in PPP, together with GPS and Glonass. Satellite orbits and clocks for all constellations are generated using a network adjustment with observation data collected by the IGS Multi-GNSS Experiment (MGEX), as well as from Fugro proprietary reference station network. The orbit processing strategy is described, and orbit accuracy for Galileo and BeiDou is assessed via orbit overlaps, for different arc lengths. Kinematic post-processed multi-GNSS positioning results are presented. The bene ts of multiconstellation PPP are discussed in terms of enhanced availability and positioning accuracy.

Ambiguity fixing in Precise Point Positioning (PPP) has been extensively studied in recent years. The provision of uncalibrated hardware delays (UHDs) to the PPP algorithm, on top of precise orbits and clocks, allows the recovery of the integer values of the carrier-phase ambiguities. Experimental results show that integer ambiguity resolution increases the accuracy in the position domain. Most of the research so far has been done on GPS, where the wide-and narrow-lane approach for ambiguity resolution has proven successful. In the context of multi-GNSS PPP, the aim of this study is to extend the method to Galileo. Initial results for UHD estimation for Galileo satellites are presented. The contribution of ambiguity-fixing to GPS + Galileo PPP is assessed. Copyright # 2016 Institute of Navigation It has been recently proven that all these approaches are equivalent [7]. Essentially, the ionosphere-free ambiguity is separated into a wideand a narrow-lane ambiguity. Wide-lane ambiguity resolution is based on the Melbourne-Wübbena geometry-free approach, while the narrow-lane ambiguity resolution is achieved via a geometry-based approach. Integer ambiguity resolution in PPP then becomes feasible when UHDs are estimated in a network adjustment and transferred to the end-user. This method has been successful in increasing accuracy in GPS-based PPP. The aim of this study is to provide initial experimentation for the extension of the method to Galileo. There are four in-orbit validation (IOV) satellites in orbit, launched in October

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Satellite positioning is evolving rapidly, with the deployment of Galileo and BeiDou systems, in addition to the modernisation programmes for GPS and GLONASS. At the time of writing, the BeiDou constellation consists of 5 Geostationary Orbit (GEO), 5 Geosynchronous Orbit (IGSO) and 4 Medium-Earth Orbit (MEO) satellites. The constellation design is particularly interesting as it allows visibility of a sufficient number of BeiDou satellites over Asia for autonomous positioning. In this paper, possibilities for real-time precise point positioning (PPP) using BeiDou are explored.