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Global navigation satellite system (GNSS) precise point positioning (PPP) has potential as an alternative or replacement for real-time kinematic (RTK) processing. In this work, we reached for RTK levels of performance without the need for local information through PPP (i.e., centimeter-level positioning that was reached near-instantaneously). This work makes use of information currently available from processing signals from global positioning system (GPS), Galileo, BeiDou-2/3, and GLONASS by fixing ambiguities for the first three constellations on all available frequencies. This processing was done using a four-frequency, four-constellation uncombined decoupled clock model (DCM) that has been expanded as part of this work. The results were tested on 1448 global datasets and showed that instantaneous convergence on average to 2.5 cm error can be achieved for 81% of the stations. These findings were reinforced by the results of epoch-by-epoch processing, as an average of 80% of all single epochs converged below 2.5 cm error at 1σ, as opposed to less than the 0.5% typically observed for classic PPP. [ABSTRACT FROM AUTHOR]

This study evaluates the feasibility of achieving improved positioning accuracy with raw GNSS measurements from recently released smartphones. Using Precise Point Positioning (PPP) as the processing mode, positioning accuracy of selected newly available devices are analyzed. These devices include Xiaomi Mi8, Google Pixel 3, Huawei Mate 20 and Samsung Galaxy S9. The key research questions to be answered are: (1) Given the hardware limitations, what PPP processing changes can be implemented to make use of the raw measurements? (2) What is the best performance that can be achieved with multi-GNSS PPP given the usage of the smartphones by the user? [ABSTRACT FROM AUTHOR]