This chapter explored the fundamentals of Global Positioning System (GPS) technology, including its historical development, the evolution of navigation techniques, its operational mechanisms, GPS chronology, satellite systems, and functional segments. Over time, GPS has become an indispensable tool for navigation, surveying, tracking, and numerous other applications. By delving into the principles and concepts underlying this pervasive technology, readers gain valuable insights into its foundational ideas and transformative impact. The chapter examined the operation and components of the GPS system, comprising the space, control, and user segments. The space segment includes a constellation of Earth-orbiting satellites, while the control segment consists of ground-based stations that monitor and manage satellite orbits. The user segment involves GPS receivers used by individuals or devices to process satellite signals for positioning and navigation. The GPS system operates on the principle of trilateration, where a receiver determines its precise location by measuring distances to multiple satellites. By receiving signals from at least four satellites and calculating the time taken for these signals to travel, the receiver determines distances using the speed of light. Accurate timekeeping is essential for GPS functionality, as satellite transmissions provide precise timing data to synchronize with receivers. The chapter also addressed factors affecting GPS accuracy, including signal blockages, atmospheric interference, and satellite geometry. The chapter concluded by examining the diverse applications of GPS technology. From personal navigation and vehicle tracking to aviation, agriculture, and emergency services, GPS has transformed how people navigate and interact with the world. It has become an essential part of daily life, facilitating efficient transportation, outdoor activities, geolocation services, and precise timekeeping for financial and telecommunications systems.