Testing of PPP Solution Aided with Enhanced Algorithms of Integer Ambiguity Resolution

Jose Luis Carretero, Cecilia Mezzera, Pedro Navarro, Pedro Roldán, Guillermo Tobías, Lucía Tomaino

Abstract:	PPP Algorithms take advantage of the low noise associated to carrier phase measurements of the GNSS signals to provide an accuracy in the range of centimeters. However, the use of carrier phase measurements requires the proper estimation of ambiguities. The fact that some combinations of ambiguities are an integer multiple of the wavelength allows to improve the time needed to properly estimate them and the accuracy of the resulting estimation. This can be done through the use of Integer Ambiguity Resolution (IAR) algorithms, which have become during the last few years one of the major advancements in precise positioning. Algorithms of IAR have an impact both on the generation of precise orbits and clocks for the GNSS satellites and on the use of these precise products for the positioning at user level. In the first case, algorithms are mostly focused on the computation of double differences to remove the impact of satellite and station biases, and on the fixing of those ambiguities that are close enough to an integer. The selection of the combinations of frequencies and observables is a key element in the effective execution of these algorithms. In this sense, the use of wide-lane combinations as first step to the complete ambiguity resolution has shown to be the optimal choice. Apart from the significant improvements observed in the estimated orbits and clocks, the IAR algorithms have been widely applied at user level for improving the positioning solution (PPP). At user level, the provision of phase biases allows to fix integer ambiguities by performing single differences and applying searching methods. Integer Ambiguity Resolution works best for PPP algorithms when ionospheric corrections are used, allowing for both a shorter convergence time and a better accuracy of the estimated delays. The use of IAR algorithms with accurate ionospheric corrections has shown very promising results in terms of convergence time and positioning accuracy. Our magicPPP service provides phase biases and ionospheric corrections to the algorithm, which implements IAR to obtain very fast convergence and accuracy in the centimetre level. In this work, the results of a dedicated experimentation campaign will be presented, including static and kinematic PPP scenarios with different environmental conditions and receiver types, based on our magicPPP system (www.magicgnss.gmv.com). These scenarios show the improvement in performance associated to enhanced IAR algorithms and their combination with ionospheric corrections.
Published in:	Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019) September 16 - 20, 2019 Hyatt Regency Miami Miami, Florida
Pages:	1841 - 1869
Cite this article:	Carretero, Jose Luis, Mezzera, Cecilia, Navarro, Pedro, Roldán, Pedro, Tobías, Guillermo, Tomaino, Lucía, "Testing of PPP Solution Aided with Enhanced Algorithms of Integer Ambiguity Resolution," Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019), Miami, Florida, September 2019, pp. 1841-1869. https://doi.org/10.33012/2019.17088
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