Resolution of these ambiguities convert the carrier-phases into precise pseudorange measurements, with measurement noise at the centimetre-to-millimetre level compared to the metre-to-decimetre-level of the direct pseudoranges (Collins et al. Ambiguity resolution in PPP (PPP-AR) requires the equipment delays within the GPS measurements to be mitigated, which would allow for resolution of the integer nature of the carrier-phase measurements (Laurichesse and Mercier 2007 Collins 2008 Mervart et al.

Differencing of simultaneous observations can be thought of as an optimal correction method (Collins and Bisnath 2011) as the error sources are not modelled. In RTK, the integer nature of the carrier-phase ambiguities is uncovered by explicitly differencing simultaneous observations from multiple stations visible to the same satellites. However, measurements of the carrier-phases are ambiguous, relative to those of the pseudoranges by an unknown number of integer cycles. The carrier-phase signals are approximately two orders of magnitude more precise than the primary pseudorange (code) signals. Precise Point Positioning (PPP) requires a relatively long initialization period of at least a few tens of minutes for the carrier-phase ambiguities to converge to constant values and for the solution to reach its optimal precision. The least accurate solution was obtained using the IRC (CNT) products, which was due to the products being archived real time products. To confirm this, FCBs generated using GRG orbit and clock products were also examined and comparable performance was observed between the FCBs and IRC (GRG) products. This is attributed to the products being generated using final IGS orbit and clock products. Of the four solutions, FCB products had the highest accuracy. Equivalent performance was noted utilizing the different methods. The convergence time (time to first fix and time to a pre-defined performance level), position precision (repeatability), position accuracy and solution outliers are examined. The novelty of the research is in the analysis of using the transformed products. Interoperability of the different PPP-AR products is a challenging task due to the public availability of different quality of products, limited literature documenting the conventions adopted within the network solution of the providers and unclear definitions of the corrections. The presented research examines the PPP-AR products generated from the FCB (Fractional Cycle Bias) model and IRC (Integer Recovery Clock) model that have been transformed into the DC (Decoupled Clock) format and applied within the PPP user solution. These include School of Geodesy and Geomatics at Wuhan University (SGG-WHU), Natural Resources Canada (NRCan) and Centre National dвЂ™Etudes Spatiales (CNES). There are currently three main public providers of real-time products that enable PPP-AR. The ability to provide multiple solutions would increase the reliability of the solution for, e.g., real-time processing if there were an outage in the generation of one set of PPP-AR products, the user could instantly switch streams to a different provider. Interoperability of different PPP-AR products would allow the PPP user to transform independently generated PPP-AR products to obtain multiple fixed solutions of comparable precision and accuracy with limited changes required to user PPP measurement processing software.

Integer ambiguity resolution of carrier-phase measurements from a single receiver can be implemented by applying additional satellite corrections (products) to mitigate unmodelled satellite equipment delays.

Ppp frame vertical format