The Global Positioning System (GPS) is a satellite-based navigation system that provides location and time information anywhere on Earth with clear sky access to GPS satellites. Originally developed by the US military, GPS became freely available for civilian use and now underlies countless applications: vehicle navigation, smartphone mapping, fleet management, surveying, emergency response, fitness tracking, and precision agriculture. GPS works by calculating position based on signals from multiple satellites, achieving accuracy of a few metres for consumer devices and centimetres for specialized equipment. Municipalities use GPS extensively: tracking service vehicles for efficiency and accountability, surveying for engineering projects, mapping infrastructure, coordinating emergency response, and providing transit arrival information. GPS data raises privacy considerations when tracking individual movements. Alternative satellite navigation systems include Russia's GLONASS, Europe's Galileo, and China's BeiDou.