PPP

The article presents an extended analytical review of the current state, historical development, technical characteristics, experimental results, application areas, and prospects of low-cost GNSS receivers (LC GNSS). Single-frequency (SF-LC), dual-frequency (DF-LC), and multi-frequency (MF-LC) models are considered with an analysis of positioning accuracy, stability, multi-path effects, antenna, and software compatibility. The paper demonstrates advantages and limitations of LC GNSS receivers in geodesy, navigation, structural health monitoring, agriculture, and atmospheric studies.

In 2022, Galileo, the European GNSS, launched the first phase of its HAS (High Accuracy Service) initiative. With free and global corrections for clock delays and satellite orbits, Galileo HAS provides decimeter positioning accuracy without additional ground networks. This research aims to evaluate the advancements in precise positioning technologies, focusing on the Galileo High Accuracy Service (HAS). The study highlights the importance of precision positioning methods, including Standard Point Positioning (SPP), Real-Time Kinematic (RTK), and Precise Point Positioning (PPP).