Performance of Ion-Free and GRAPHIC Combinations in Multi-GNSS PPP under Different Ionospheric Conditions in Brazil

Assessing Galileo ionosphere-free combinations: impacts of contrasting equatorial ionospheric conditions

This study investigates the impact of Galileo ionosphere-free (IF) dual-frequency combinations on the performance of Precise Point Positioning (PPP). Four IF combinations were analyzed: E1–E5a, E1–E6, E1–E5b, and E1–E5 (AltBOC). The analysis was conducted using 60 days of GNSS data from seven Brazilian stations located...

Pulsar Constellation Evolution and PPP Convergence using LEO GNSS

The objective of this paper is to demonstrate the future impact of a dedicated low-earth-orbit (LEO) Global Navigation Satellite System (GNSS) on positioning, navigation, and timing (PNT), in addition to a reflective discussion on how common GNSS evaluation methods can best reflect LEO satellite dynamics. This paper wi...

Elevation-cutoff-dependent convergence and steady-state performance of LEO-augmented multi-GNSS PPP time transfer

Under restrictive elevation-cutoff conditions, Global Navigation Satellite System (GNSS) precise point positioning (PPP) time transfer can suffer delayed convergence because fewer satellites are available and the timing geometry degrades. However, it remains unclear whether low Earth orbit (LEO) geometric augmentation...

Constellation-Dependent GNSS PWV Retrieval Under Humid Conditions in Beijing

Noncollocation can obscure small constellation-dependent differences in Global Navigation Satellite System (GNSS) precipitable water vapor (PWV). We assessed five constellation configurations processed with a common precise point positioning strategy at the same four physical station groups surrounding the Beijing radi...

Ingesting Ionospheric Characteristics for Regional Improvement of Galileo Single-Frequency Ionospheric Correction Algorithm

As part of the Global Navigation Satellite System (GNSS), Galileo uses the NeQuick-G algorithm to provide ionospheric correction to single-frequency users. Within the framework of a research project, an improved Galileo single-frequency ionospheric correction approach has been proposed by incorporating regional ionosph...

An augmented zenith tropospheric delay model for marine scenarios and its PPP application