Improving Performances of Classic Three Carrier Ambiguity Resolution (TCAR) Algorithms for Galileo using GTCAR

Javier Simon, Belén Martín Peiró, Manuel Toledo

Abstract:	High precision applications require the use of carrier phase measurements, with precision theoretically in the millimeter to centimeter level, not achievable by code measurements. However, in order to use the high precision of carrier phase observables it is necessary to solve the integer ambiguities inherent to this kind of measurements. GMV developed an algorithm for the resolution of the phase ambiguities, Generalized Three Carrier Ambiguity Resolution (GTCAR, presented in ION GPS 99 conference [1]), which identifies among all the generic integer linear combinations of the code and phase observables available at the different frequencies those combinations that optimize the achievable performances of ambiguity validity. The objective of this study is to show the performances achievable with GTCAR algorithm using combinations of Galileo and GPS signals. Due to the nature of GTCAR, this study shows the theoretical limit of the performances achievable in ambiguity resolution techniques combining up to three frequencies. Results obtained show that GTCAR algorithm improves the performances of standard Three Carrier Ambiguity Resolution (TCAR) algorithms [2]. GTCAR performances allow the resolution of the phase ambiguities and the use of the high precision of phase measurements considering the appropriate linear combinations of frequencies in each case. This is an important result considering that Galileo and GPS will transmit signals in three different frequencies in the future. This GTCAR algorithm is not only a method to check theoretical limits achievable by ambiguity resolution techniques, but also an operational alternative to currently used ambiguity resolution methods
Published in:	Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008) September 16 - 19, 2008 Savannah International Convention Center Savannah, GA
Pages:	2868 - 2879
Cite this article:	Simon, Javier, Peiró, Belén Martín, Toledo, Manuel, "Improving Performances of Classic Three Carrier Ambiguity Resolution (TCAR) Algorithms for Galileo using GTCAR," Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008), Savannah, GA, September 2008, pp. 2868-2879.
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