Hi Michael,
Thank you for your thoughtful and detailed comment. I appreciate your expertise and the opportunity to clarify some points.
You’re absolutely right that GNSS refers to the overarching system, while SPP (Single Point Positioning) and RTK are specific methods or techniques of utilizing GNSS signals. My article aimed to focus on the practical applications of GNSS and RTK in different contexts rather than delve into the technical classifications.
Many thanks for the comment!