REDUCING THE CONVERGENCE TIME OF THE MULTI-GNSS UNCOMBINED PPP

• Grant number: 24/22757-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: July 01, 2025
• End date: February 28, 2029
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geodesy
• Principal Investigator: Daniele Barroca Marra Alves
• Grantee: João Pedro Voltare Zaupa
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

Precise Point Positioning (PPP) has emerged as an attractive alternative to relative positioning for activities requiring high precision, and its performance can benefit from the combination of multiple GNSS systems. Classical PPP typically relies on the ionosphere-free combination of dual-frequency observations, which limits its flexibility in multi-frequency scenarios. Additionally, linear combinations are known to amplify measurement errors. The main operational challenge of the method is its long convergence time, on the order of tens of minutes, needed for the solution to reach centimeter-level accuracy. Various factors are being investigated to reduce this time, including the use of additional frequency uncombined (UDUC) observations, correct integer ambiguity resolution (PPP AR), and proper modeling of tropospheric and ionospheric delays. Thus, this research aims to develop a multi-frequency, multi-GNSS UDUC PPP model that efficiently resolves ambiguities for Brazil's challenging atmospheric conditions, with the goal of minimizing convergence time.