This paper examines the use of Global Navigation Satellite System (GNSS) technologies for Structural Health Monitoring (SHM) of strategic structures, with particular attention to offshore installations and critical infrastructure. The study reviews current GNSS methodologies for structural monitoring, analysing both static and kinematic positioning techniques, including Real-Time Kinematic (RTK) and Precise Point Positioning (PPP). The integration of multi-constellation GNSS data for enhanced monitoring accuracy is discussed through examples from offshore wind turbines and marine platforms, where traditional monitoring systems often face practical and environmental constraints. Results reported in the literature show that GNSS-based monitoring systems can achieve millimetre-level displacement accuracy while maintaining continuous operation even in demanding conditions. Technical issues such as multipath effects and atmospheric interference are typically mitigated through advanced filtering procedures and sensor-integration strategies. Overall, the review suggests that GNSS-based SHM represents a viable option for continuous structural assessment, particularly in environments where conventional instrumentation is difficult to deploy. The analysis aims to support the development of improved monitoring approaches for the management and maintenance of critical infrastructure. 

Keywords: GNSS, structural health monitoring, SHM, offshore platforms, offshore wind, RTK, PPP, high-rate GNSS, sensor fusion.